Reland [heap] Avoid the use of cells to point from code to new-space objects.

src/heap/heap.h

Index: src/heap/heap.h
diff --git a/src/heap/heap.h b/src/heap/heap.h
index ed1e65253e89a03a4135886046919d98f639bd70..7f03d89abe43d005b325ea7a09122979e3794ed0 100644
--- a/src/heap/heap.h
+++ b/src/heap/heap.h
@@ -194,6 +194,11 @@ using v8::MemoryPressureLevel;
   V(FixedArray, detached_contexts, DetachedContexts)                           \
   V(ArrayList, retained_maps, RetainedMaps)                                    \
   V(WeakHashTable, weak_object_to_code_table, WeakObjectToCodeTable)           \
+  /* weak_new_space_object_to_code_list is an array of weak cells, where */    \
+  /* slots with even indices refer to the weak object, and the subsequent */   \
+  /* slots refer to the code with the reference to the weak object. */         \
+  V(ArrayList, weak_new_space_object_to_code_list,                             \
+    WeakNewSpaceObjectToCodeList)                                              \
   V(Object, weak_stack_trace_list, WeakStackTraceList)                         \
   V(Object, noscript_shared_function_infos, NoScriptSharedFunctionInfos)       \
   V(FixedArray, serialized_templates, SerializedTemplates)                     \
@@ -860,6 +865,9 @@ class Heap {
     return new_space_.IsAtMaximumCapacity() && maximum_size_scavenges_ == 0;
   }
 
+  void AddWeakNewSpaceObjectToCodeDependency(Handle<HeapObject> obj,
+                                             Handle<WeakCell> code);
+
   void AddWeakObjectToCodeDependency(Handle<HeapObject> obj,
                                      Handle<DependentCode> dep);
 
@@ -1120,6 +1128,8 @@ class Heap {
 
   // Write barrier support for object[offset] = o;
   inline void RecordWrite(Object* object, int offset, Object* o);
+  inline void RecordWriteIntoCode(Code* host, RelocInfo* rinfo, Object* target);
+  void RecordWriteIntoCodeSlow(Code* host, RelocInfo* rinfo, Object* target);
   inline void RecordFixedArrayElements(FixedArray* array, int offset,
                                        int length);